SVN client error "The server at [...] does not support the HTTP/DAV protocol"
Solution 1:
You get this error message because the URL is invalid. It leads to a web interface (i.e. a web client) and Subversion clients do not know how to parse this URL. Please, see the following article - KB102: Subversion client errors caused by inappropriate repository URL.
Solution 2:
The comment by Bahrep is the correct answer, but since in the comments there seems to be some confusion, I decided to elaborate further. "The error indicates that the URL used to address the repository using Subversion client is inappropriate. Most likely, the URL was copied from the web browser's address bar when exploring the repository through the web interface of VisualSVN Server. Subversion client programs are not capable of handling the syntax of such URLs. The appropriate URLs should be obtained by clicking the Checkout button in the web interface." I got this error because I used browser link in the toroise interface, but I should instead click "copy repository url" in the svn and use that link. As simple as that!